(i) Field of the Invention
The present invention relates to a method for preparing a molded article of a crosslinked polyolefin and the molded article More specifically, it relates to a method for preparing a molded article of a crosslinked polyolefin which comprises treating a mixture of a specific copolymer and a specific unsaturated compound with a catalyst, and the molded article.
(ii) Description of the Prior Art
For the purpose of improving mechanical properties, solvent resistance and heat resistance of molded articles of a polyolefin, it has been widely known to crosslink the polyolefin. Various techniques for crosslinking have already been suggested, and there have been known a method which comprises mixing a bifunctional monomer and a radical generator with a polyolefin, followed by heating and melting to achieve crosslinking; a method which comprises copolymerizing a monomer having a hydrolyzable group such as a alkoxysilane with an olefin to form a copolymer, molding it and then treating the molded copolymer with boiling water to perform a hydrolytic reaction, thereby forming an Si--O--Si bond, whereby crosslinking is achieved (Japanese Patent Application Laid-open No. 58-117244); and a method which comprises irradiating a molded article of a polyolefin with radiation to achieve crosslinking. In addition, there is also a method suggested by the present inventors which comprises copolymerizing an alkenylsilane with an olefin, and then treating the resultant copolymer with a catalyst to form an Si-C bond and to thereby achieve crosslinking (Japanese Patent Application Laid-open No. 3-106951).
These suggested methods can provide a crosslinked polyolefin, but its crosslinking density is not considered to be sufficiently high. Even when the crosslinking density is low, the heat resistance of molded articles obtained therefrom can be fairly improved, but in order to utilize the crosslinked molded articles as structures or in order to improve solvent resistance at high temperatures, it is desired to further increase the crosslinking density.